<?php

/**
 * A class to describe a geodetic location
 *
 * This package is not tied to any specific datum. For general applications
 * GRS80 (or its equivalent NAD83 or WGS84) should generally be considered.
 *
 * PHP version 5
 *
 * LICENSE:
 *
 * Copyright (c) 2007-2009, Philippe Jausions / 11abacus
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   - Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   - Neither the name of 11abacus nor the names of its contributors may
 *     be used to endorse or promote products derived from this software
 *     without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @category  Structures
 * @package   Structures_Location
 * @author    Philippe Jausions <Philippe.Jausions@11abacus.com>
 * @copyright 2007-2009 by Philippe Jausions / 11abacus
 * @license   http://www.opensource.net/licenses/bsd-license.php New BSD
 */

/**
 * Required dependencies
 */
require_once 'Structures/Location/GeodeticInterface.php';
require_once 'Structures/Location/Exception.php';

/**
 * A class to describe a geodetic location
 *
 * @category Structures
 * @package  Structures_Location
 * @author   Philippe Jausions <Philippe.Jausions@11abacus.com>
 */
class Structures_Location_Geodetic 
implements Structures_Location_GeodeticInterface
{
    /**
     * Longitude (decimal degrees)
     *
     * @var float
     */
    protected $longitude = 0.0;

    /**
     * Latitude (decimal degrees)
     *
     * @var float
     */
    protected $latitude = 0.0;

    /**
     * Elevation/altitude/height (meters)
     *
     * @var float
     */
    protected $elevation = null;

    /**
     * Class constructor
     *
     * @param float|array $longitude
     * @param float|array $latitude
     * @param float       $elevation
     */
    public function __construct($longitude, $latitude, $elevation = null)
    {
        $this->setLongitude($longitude);
        $this->setLatitude($latitude);
        $this->setElevation($elevation);
    }

    /**
     * Returns the longitude (decimal degrees)
     *
     * @return float
     */
    public function getLongitude() 
    {
        return $this->longitude;
    }

    /**
     * Returns the latitude (decimal degrees)
     *
     * @return float
     */
    public function getLatitude()
    {
        return $this->latitude;
    }

    /**
     * Returns elevation/altitude/height (meters)
     *
     * @return float|NULL 
     */
    public function getElevation()
    {
        return $this->elevation;
    }

    /**
     * Sets the longitude
     *
     * <code>
     * // Set as numeric value  
     * $geo->setLongitude(-73.986952);
     * 
     * // Set as array value
     * $geo->setLongitude(array(73, 59, 13.0272, 'W'));
     * </code>
     *
     * @param float|array $value Longitude to set (-180 to 180) or array defining
     *                           the value
     * 
     * @return void
     */
    public function setLongitude($value)
    {
        if (is_array($value)) {
            $value = $this->convertCoordinate($value);
        }
        if (!is_numeric($value)) {
            throw new Structures_Location_Exception_Invalid('Longitude must be a float value or an array');
        } elseif (-180 > $value || $value > 180) {
            throw new Structures_Location_Exception_Invalid('Longitude must be between -180 and 180 degrees');
        }
        $this->longitude = $value;
    }

    /**
     * Sets the latitude
     *
     * <code>
     * // Set as numeric value  
     * $geo->setLatitude(40.756053);
     * 
     * // Set as array value
     * $geo->setLatitude(array(40, 45, 21.7908, 'N'));
     * </code>
     * 
     * @param float|array $value Latitude to set (-90 to 90) or array defining
     *                           the value
     * 
     * @return void
     */
    public function setLatitude($value)
    {
        if (is_array($value)) {
            $value = $this->convertCoordinate($value);
        }
        if (!is_numeric($value)) {
            throw new Structures_Location_Exception_Invalid('Latitude must be a float value or an array');
        } elseif (-90 > $value || $value > 90) {
            throw new Structures_Location_Exception_Invalid('Latitude must be between -90 and 90 degrees');
        }
        $this->latitude = $value;
    }

    /**
     * Sets elevation/altitude/height (meters)
     *
     * @param float $value Elevation to set
     * 
     * @return void
     */
    public function setElevation($value)
    {
        if (!is_numeric($value) && $value !== null) {
            throw new Structures_Location_Exception_Invalid('Elevation must be a float value');
        }
        $this->elevation = $value;
    }

    /**
     * Converts a value specified as an array into its decimal representation
     *
     * @param array $value value to convert:
     * <ol>
     *  <li>Degrees (0-90 for N/S; 0-180 for E/W)</li>
     *  <li>Minutes (0-59.99999)</li>
     *  <li>Seconds (0-59.99999) If "seconds" is not passed, "minutes" is assumed
     *                           to be a decimal number.</li>
     *  <li>Direction (N, S, E, W or O)</li>
     * </ol>
     * @param string $direction one of N, S, E, W (or O). The direction can
     *                          be passed either through this argument, or
     *                          the 4th element of the $value array. If both
     *                          are provided, the array value is considered.
     *
     * @return float the decimal value of the coordinate
     * @static
     * @throws Structures_Location_Exception_Invalid
     */
    public static function convertCoordinate($value, $direction = null)
    {
        $count = count($value);
        if ($count == 4) {
            $direction = array_pop($value);
        }
        switch (strtoupper($direction)) {
        case 'N':
            $max = 90;
            $sign = 1;
            break;
        case 'S':
            $max = 90;
            $sign = -1;
            break;
        case 'E':
            $max = 180;
            $sign = 1;
            break;
        case 'W':
        case 'O':
            $max = 180;
            $sign = -1;
            break;
        default:
            if ($direction === null) {
                throw new Structures_Location_Exception_Invalid('Missing coordinate direction');
            }
            throw new Structures_Location_Exception_Invalid('['.$direction
                                            .'] is not a valid direction');
        }
        if ($count < 2 || $count > 3) {
            throw new Structures_Location_Exception_Invalid('Wrong count of array element');
        }
        $degrees = array_shift($value);
        if ($count == 2) {
            $minutes = array_shift($value);
            $seconds = 0;
        } else {
            $minutes = floor(array_shift($value));
            $seconds = array_shift($value);
        }

        if ($degrees > $max || $degrees < 0) {
            throw new Structures_Location_Exception_Invalid('Degrees must be between 0 and '.$max);
        }
        if ($minutes >= 60 || $minutes < 0) {
            throw new Structures_Location_Exception_Invalid('Minutes must be between 0 and 59.9999...');
        }
        if ($seconds >= 60 || $seconds < 0) {
            throw new Structures_Location_Exception_Invalid('Seconds must be between 0 and 59.9999...');
        }
        return $sign * ($degrees + $minutes / 60 + $seconds / 3600);
    }
}

?>